5/5/10 (straddle)
8 handed

UTG+1 limp, 2 other limpers, I complete sb with Ah2s5s6cTd
BB complete, straddle check

Pot 60

Flop 7c5h3s

UTG pot to 60
He's a very rich man, gambler but smart, I have only played twice with him before. He's very loose and aggressive and can sometimes splash around when he's drunk or when he's loosing which wasn't the case.

I think he raises most of his A2 preflop, so he should often have a straight here.

I call 60

Turn: Qd
I check, he pot to 180, I call

River: Ad

I check, he bets 400

1) Can I fold flop? I really think he has 64 here, and the others cards are likely to be low, like A46 or 642. I perform no that well against that range.

2) Tough river spot, he's limping a lot of trash hands but it's hard to quantify how often he has a 2 in his 3 remaining cards (considering he has 64).
I'm risking 400 to win 270, so I need to be right 60% of the time.
Would you call?

No, you can't fold flop with this info. On the river, without reads, I'd assume villain might value bet worse (same low, worse high) and obv he'd always be betting his straight.

I would call river as played, and the only street i really consider folding is turn, if we take the view we are behind a better a2xxx hand.